A synthetic latex is an aqueous dispersion of finally divided polymer particles or spheres. Such dispersions are conventionally stabilized by a surfactant or emulsifying agent and are generally stable for a period of months or even years. Such lateices are generally comprised of from 20 percent to 70 percent solids and from 30 percent to 80 percent water. Even though such latices are utilized as aqueous dispersions, it is nevertheless burdensome and costly to ship such large amounts of water. For this reason it would be highly desirable to provide a resin which is a dry powder for storage and transportation purposes, but which can be reconstituted to a latex for ultimate use, in a paint, an adhesive composition, a carpet backing, a paper coating, or the like.
Redispersible powders have previously been prepared. However, the copolymers utilized in these redispersible powders generally have high acid contents (they contain a relatively large number of repeat units that are derived from monomers which contain carboxyl groups). Such redispersible powders have also been known to contain relatively large amounts of surfactants. More specifically, see The Journal of Applied Polymer Science, pp. 2249-2258 (1963) and U.S. Pat. No. 3,232,899. The utilization of high acid contents and the presence of large amounts of surfactants generally has an adverse effect on the performance of latices. For this reason heretofore a totally satisfactory redispersible resin powder composition has not been prepared.